Rotary knife with sharpener



United States Patent Oilice hio Filed Jan. 10, 1966, Ser. No. 519,677 12 Claims. (Cl. 30-138) The present invention relates to hand manipulated knives having power driven blades.

A principal object of the present invention is the provision of a new and improved hand manipulated knife comprising a blade supporting structure, a knife blade carried by the blade supporting structure, power means for rotating the blade relative to the blade supporting structure, and means carried by the blade supporting structure, either as a permanent part thereof or an attachment, for sharpening the cutting edge of the blade while the blade is moved by the power means to enable the user of the knife conveniently to maintain the blade sharp.

More particularly, it is an object of the invention to provide a new and improved hand manipulated knife having a rotary cutting blade, a substantially ring-like blade supporting structure including a handle, means to rotate the rotary blade in the structure, and a blade sharpening member carried by the structure for sharpening the blade during rotation of the blade in its support structure.

Another object of the invention is the provision of a new and improved rotary knife comprising a substantially ring-like blade supporting structure, a rotary power driven blade supported therein, a handle attached to one side of the supporting structure, and a blade sharpening member carried on the blade supporting structure adjacent the handle for sharpening the blade during rotary movement of the blade, the sharpening member being supported in a position in which it does not obstruct the passage of cut material through the central opening of the knife blade and its supporting structure.

Other objects and advantages of the invention will be apparent from the following description of a preferred form thereof, reference being made to the accompanying drawings wherein:

FIG. 1 is a perspective view of a, rotary knife embodying the invention; and

FIG. 2 is a sectional view taken along line 2-2 of FIG. l on a larger scale and showing the knife swung 90 counterclockwise to the position shown in FIG. 1.

Referring to the drawings, a rotary knife is shown comprising a hollow handle 11 attached to one side of an annular or ring-like blade supporting structure 12 which carries an annular blade 13 rotatably supported therein. The blade 13 is in the form of ring or sleeve, one end portion of which forms a base portion 14 and the other end of which is turned inwardly to 4form a cutting edge 15. The blade is rotated about its axis by power means and by pressing the side of the blade remote from the handle against a workpiece with the cutting edge against the work and drawing the knife by the handle along the workpiece, the rotating blade will sever a strip or slice from the work and which strip will pass through the opening through the blade and its supporting structure.

The rotary blade supporting structure 12 comprises -an axially split ring member 16 having an annular recess 17 in which the blade 13 is contained for rotary movement relative to the support member. The blade 13 is retained in the recess 17 by an inwardly extending annular flange 18 formed on the member 16 and projecting into a, peripheral groove 19 formed in the outside surface of the blade. The flange 18 slidingly engages the walls of the grooves 19 to prevent axial movement of the blade While per- 3,349,185 Patented oct. 31, 1967 mitting free rotation thereof. The ring member 16 is preferably Iformed of a resilient metal so that it can be spread at the split therein to accommodate insertion of the blade 13 into the recess 17, and when the spreading force is released the member retracts and engages the flange 18 inthe blade groove 19.

The ring member 16 is attached to the base 20 of `the handle 11 by two screws 21, 22 extended through openings in two securing flanges or lugs 23 formed on the ring member at each side of the split therein and threaded into openings, not shown, in the handle base. The screws 21, 22 not only secure the ring member 16 to the handle but serve to prevent spreading of the member. The portion of the base 20 of the handle 11 to which the lugs 23 of the member 16 are attached has the same general configuration as the lugs and is curved on a diameter corresponding to that of the normal diameter of the member.

The base 14 of the blade 13 has axially projecting gear teeth 24 formed about the inner end thereof which mesh with a drive gear 25. The gear 2S is attached of a shaft 26 which is journaled in a bushing 27 and bearing 2S in the handle 11 and the gear is disposed in a shallow circular chamber 30 formed in the ring member 16 and the lugs 23 thereof. The recess 30 opens into the recess 17 and a sector of the gear 25 ext-ends into the last-mentioned recess and engages the teeth 24 of the blade 13.

The shank 26 is connected to a suitable motor driven flexible shaft, not shown, which is attached to the outer end of the handle 11 and which drives the gear 25 while the knife is manipulated by the operator gripping the handle. The drive for the gear may be similar to that shown in United States Patent No. 3,024,532 which discloses another form of a rotary knife somewhat similar to that disclosed herein. Furthermore, suitable means may be provided for lubricating the engaging surfaces of the ring member 16, blade 13 and the gear drive for the blade; however, for simplification these means are not shown.

It will be seen that as the blade 13 is rotated by the gear 25, the knife can be manipulated so that the portion of the blade remote from the handle can be addressed to the work to be cut at an angle and the knife drawn in a direction toward the handle to sever -a strip or slice from the work which passes through the rotary blade and its support.

In using the knife, it is desirable from time to time to sharpen the cutting edge 15 of the blade Vand this may be conveniently and quickly accomplished in accordance with the present invention by a sharpening means 31 on the ring member 16 adjacent the base 20 of the handle and located in the central area of the blade Iand ring member through which the work passes. The sharpening means 31 comprises a bushing member 32 attached to the blade support member and the handle 11 by the screws 21, 22 which extend through openings through iianges 33, 34, extending from opposite sides of the bushing and which are curved to conform to the inside of the ring 16. The bushing 32 has a bore 35, the extended center line of which slopes generally radially outwardly with respect to the axis of rotation of the blade 13 and extends yadjacent the cutting edge 15 of the blade. A tubular member 36 is slidingly received in `the bore 35 and the upper end thereof, as viewed in FIG. 2, has the hollow shank 37 of a knurled knob 40 threaded therein. The lower end of the tubular member 36, which is formed of a hard steel commonly used for sharpening knife blades, is enlarged as at 41 and forms 4a head, the outer end surface of which has a central recess providing an annular surface which is Vadapted to engage the inner surface of the blade 13 in an area `adjacent the cutting edge 15 thereof for sharpening the blade. Preferably, the center line of the bore 35 lies in a plane which intersects the rotary blade approximately one-half degree from normal to the blade `so that the blade is engaged by one edge portion only of the sharpening head. It will be understood that the shape of the sharpening head and the angular position in which the member 36 is supported relative to the blade can be varied as desired as long as the sharpening head is effective to sharpen the cutting edge. The lower 4portion of the bore 35 is counterbored to receive the head 41, and a ycompression spring 4Z surrounds the shank 37 and reacts between the upper face of the member 32 and the underside of knob 40 to normally urge the member 36 upwardly into the bore 35 with the blade sharpening head thereof nesting in the counterbore.

The knob 40 provides means by which the operator of the knife may conveniently grasp and shift the member 36 from its normal position, shown in full lines, to engage one side of the face of the sharpening head 41 with the blade 13 and to rotate the sharpening head during sharpening of the blade, preferably in the direction to move the portion or side of the face of the head outwardly of the blade 13, that is, towards the cutting edge.

A rod 43 having a knurled knob 44 attached to one end extends through laligned openings through the knob 40 and the tubular member 36, and projects beyond the cutting edge 15 of the blade 13. The extended end of the rod 43 has a blade sharpening head 45 formed thereon which is preferably formed of hard steel of the type used to sharpen knife blades. The outer end of the head 45 is cylindrical and a frusto-conieal section 46 interconnects the cylindrical portion and the rod proper, which secion is adapted to tangentially engage the outer surface of the blade 13 adjacent the cutting edge 15 when the rod is drawn upwardly, as shown in broken lines. The knob 44 provides -a convenient means by which the operator may grasp and draw the rod 36 upwardly from its normal position to engage the head 45 with the blade and to rotate the head while the cutting edge is sharpened.

The rod 43 is urged to the position shown in full lines in FIG. 2 by a `compression spring 50 which surrounds the rod and reacts against the end of a collar 51, which is attached to the rod, and the inner end of the shank 37. The inside diameter of the member 36 adjacent the counterbore receiving the head 41 is such as to accurately guide the -rod 43 during longitudinal movements thereof and the shoulder 52 formed by the reduction in diameter of the member forms a stop which is engaged by the collar 51 fixed to the rod 43 to limit the movement of the rod by the spring 50.

It will be appreciated that during usage of the knife, when it becomes desirable to sharpen the blade 13 the operator, without stopping the rotation of the blade, holds the handle 11 in one hand and depresses and rotates the knob 40 with the other hand to bring the edge of the face of the head 41 into engagement with the inner edge of the rotating blade 13, as shown in FIG. 2 in broken lines to sharpen the blade. The inside surface of the blade 13 at the cutting edge thereof moving while engaged by the head 41 is quickly sharpened. The knob 40 is released after a brief sharpening action and the member 41 returns to its inoperative position. The operator then draws the knob 44 outwardly which moves the sharpening surface 46 into engagement with the outer surface of the blade at the cuting edge 15, as seen in broken lines in FIG. 2, which subjects the periphery of the outer surface at the cutting edge of the blade to sharpening action of the surface 46 of the head 45. Upon releasing the knob 44, the spring 50 returns the rod 43 to its normal position shown in full lines. During the sharpening operation the operator slowly rotates the knob 44 preferably in the direction to move the engageing portion of the head 45 towards the edge of the blade. It is to be understood that the shape of the surface 46 `of the head 45 can be varied from that shown to meet any desired requirement. The operator may quickly and conveniently sharpen the blade with a minimum of time lost in the work cutting operations.

By locating the blade sharpening means 31 adjacent the base 20 of the handle, the opening through the blade support structure is unobstructed to the Ipassage of the strips or slices of work passing therethrough and the operating knobs 40, 44 for the sharpening members 41, 46 are convenient for manipulation by the operator while holding the knife by the handle thereof.

It will be apparent that the invention provides an effective lmeans for sharpening power actuated bladesof hand knives while the knives are held by the operators so that the blades can be maintained sharp with a minimum of distraction and time diverted from cutting operations. The sharpening means is compact and is supported in a manner to avoid interference with normal manipulations of the knives during use thereof.

It will be understood that although I have shown the sharpening members 41 and 45 comprised of steel, they could be formed of any other suitable sharpening material, such as emory or the like.

While but one form of the invention has been shown and described, it will be understood that other forms, modifications and adaptations could be made all falling within the scope of the claims which follow.

Having described my invention, I claim:

1. A hand manipulated knife comprising a blade supporting structure substantially annular in shape and including a handle projecting from one side thereof, a blade supported by said structure, said blade being substantially ring-shaped and including an annular end projecting from said support structure and having an inwardly turned end portion providing an annular cutting edge, means to move said blade relative to said structure for effecting cutting of work engaged by said blade, and blade sharpening means carried by said support structure, said blade sharpening means comprising a shaft-like member extending away from said cutting edge of said blade and toward the axis about which the blade rotates, bushing means located adjacent the juncture of said handle and said annular support means, said bushing means supporting said shaft-like member for reciprocable movement longitudinally in a direction radially and axially of the axis of rotation of said blade for engaging one end of said shaft-like member with a surface at said cutting edge of said blade.

2. A hand manipulated knife comprising a blade supporting structure substantially annuar in shape and including a handle projecting from one side thereof, a blade supported by said structure, said blade being substantially ring-shaped and including an annular end projecting from said support structure providing an annular cutting edge, means to rotate said blade relative to said structure about a central axis of the blade that extends through the plane of the annular cutting edge for effecting cutting of work engaged by said blade, and blade sharpening means carried by said support structure, said blade sharpening means comprising a shaft-like member extending away from and inwardly of said annular cutting edge of said blade and bushing means located adjacent the juncture of said handle and said annular support means, said bushing means supporting said shaft-like member for reciproeable movement axially of the axis of rotation of said blade for engaging a sharpening surface adjacent one end of said shaft-like member with a surface at said cutting edge of said blade.

3. A hand manipulated knife comprising an annular blade supporting structure including a handle; an annular blade movably supported by said structure for rotation about its central axis, said blade having a circular cutting edge and the blade and supporting structure providing a central area through which portions of work cut by the blade can pass; means to rotate the blade relative to the structure to cut work engaged by the blade; and a blade Sharpener assembly in said central area carried by the supporting structure, said blade sharpener assembly including a member having a sharpening surface located adjacent the cutting edge of the blade, means mounting the member for reciprocable movement along a path inclined to the blade into and out of contact with a surface of the blade at the cutting edge, and a hand grasp adjacent to the end of said member remote from the sharpening surface for engagement yby an operator to reciprocate said member.

4. A knife as defined in claim 3 wherein the hand grasp is rigidly connected to the sharpening surface.

5. A hand manipulated knife comprising an annular blade supporting structure including a handle; an annular blade movably supported by said structure for rotation about its central axis, said blade having a circular cutting edge and the blade and supporting structure providing a central area through which portions of work cut by the blade can pass; means to rotate the blade relative to the structure to cut Work engaged by the blade; and a blade Sharpener assembly in said central area carried Iby the supporting structure, said blade Sharpener assembly including a member having a sharpening surface located adjacent the cutting edge of the blade, means mounting the member for rotational movement about a central axis of the sharpening surface and for reciprocable movement along a path inclined to the blade into and out of contact With a surface ofthe blade at the cutting edge, and a hand grasp adjacent to the end of said member remote from the sharpening surface for engagement by an operator to reciprocate and rotate said member.

6. A hand manipulated knife comprising an annular blade supporting structure including a handle; an annular blade movably supported by said structure for rotation about its central axis, said blade having a circular cutting edge and the blade and supporting structure providing a central area through which portions of work cut by the lblade can pass; means to rotate the blade relative to the structure to cut work engaged by the blade; and a blade sharpener assembly in said central area carried by the supporting structure, said blade Sharpener assembly including a first member having a sharpening surface located adjacent the cutting edge of the blade, means mounting the first member for reciprocable movement along a path inclined to the blade into and out of contact with a surface of the blade at the cutting edge, a hand grasp adjacent to the end of said first member remote from the sharpening surface for engagement by an operator to reciprocate said first member, a second member having a sharpening surface located adjacent the cutting edge of the blade spaced from the sharpening surface of the first member, means mounting the second member for reciprocable movement independent of said first member along a path inclined to the blade into and out of contact with a surface of the blade at the cutting edge, and a hand grasp adjacent to the end of said second member remote from the sharpening surface for engagement by an operator to reciprocate said second member independently of said first member.

7. A knife as defined in claim 6 wherein the second member extends across the cutting edge of the blade through the plane of the circular cutting edge from within the said central area.

8. A hand manipulated knife comprising an annular blade supporting structure including a handle; an annular blade movably supported by said structure for rotation about its central axis, said blade having a circular cutting edge and the blade and supporting structure providing a central area through which portions of Work cut by the blade can pass; means to rotate the blade relative to the structure to cut Work engaged by the blade; and a blade Sharpener :assembly in said central area carried by the supporting structure, said blade Sharpener assembly including first shaft-like member having a sharpening surface located adjacent the cutting edge of the blade, means mounting the first member for rotational movement labout a central axis of the sharpening surface and for reciprocable movement along a path inclined to the blade into and out of contact with a surface of the blade at the cutting edge, a hand grasp adjacent to 4the end of said first member remote from the sharpen ing surface for engagement by an operator to reciprocate said first member, a second shaft-like member extending longitudinally through the first member and having a sharpening surface located adjacent the cutting edge of the blade spaced rfrom the sharpening surface of the first member, means mounting the second member for rotational movement independent of said first member about a central axis of its sharpening surface and for reciprocable movement independent of said first member along a path inclined to the blade into and out of contact With a surface of the blade at the cutting edge, and 'a hand grasp adjacent to the end of said second member remote from the sharpening surface for engagement by an operator to reciprocate and rotate said second member independently of said first member.

9. A knife as defined in claim 8 wherein the said first and second members are elongated in the direction in which they are reciprocable and said second member extends across the cutting edge of the blade through the plane of the circular cutting edge from within the said central area.

10. In a hand knife having an annular cutting blade and a blade supporting structure, a blade-sharpening apparatus comprising: a first shank-like member having a sharpening surface at one end thereof; means forming a guide for supporting said member for longitudinal and rotational movement and adapted to be secured to said blade supporting structure; a hand grasp adjacent to the end of said first member remote from the sharpening surface for engagement by an operator to reciprocate and rotate said first member; a second shank-like member having a portion coextensive with said first member and an end portion extending beyond said one end of said r first member, said end portion having la sharpening surface facing said sharpening surface of said first member; means supporting said second member 4adjacent said first member for independent parallel longitudinal relative movement and for independent rotational movement; and a hand grasp adjacent to the end of said second member remote from the sharpening surface for engagement by an operator to reciprocate and rotate said second member independently of said first member.

11. Apparatus as defined in claim 10 wherein said first member is tubular and said second member has a section slidably supported inside said first member.

12. Apparatus as defined in claim 11 wherein the means to move the members longitudinally and rotatably are rigidly connected with respective sharpening surfaces.

References Cited UNITED STATES PATENTS 1,051,646 1/ 1913 Stukart 51-248 2,694,887 11/ 1954 Green et al 51-248 2,701,911 2/ 1955 Maescher 30-139 X 3,024,532 3/ 1962 Bettcher 30-276 FOREIGN PATENTS 284,336 6/ 1928 Great Britain.

WILLIAM FELDMAN, Primary Examiner.

G. WEIDENFELD, Assistant Examiner. 

3. A HAND MANIPULATED KNIFE COMPRISING AN ANNULAR BLADE SUPPORTING STRUCTURE INCLUDING A HANDLE; AN ANNULAR BLADE MOVABLY SUPPORTED BY SAID STRUCTURE FOR ROTATION ABOUT ITS CENTRAL AXIS, SAID BLADE HAVING A CIRCULAR CUTTING EDGE AND THE BLADE AND SUPPORTING STRUCTURE PROVIDING A CENTRAL AREA THROUGH WHICH PORTIONS OF WORK CUT BY THE BLADE CAN PASS; MEANS TO ROTATE THE BLADE RELATIVE TO THE STRUCTURE TO CUT WORK ENGAGED BY THE BLADE; AND A BLADE SHARPENER ASSEMBLY IN SAID CENTRAL AREA CARRIED BY THE SUPPORTING STRUCTURE, SAID BLADE SHARPENER ASSEMBLY INCLUDING A MEMBER HAVING A SHARPENING SURFACE LOCATED ADJACENT THE CUTTING EDGE OF THE BLADE, MEANS MOUNTING THE MEMBER FOR RECIPROCABLE MOVEMENT ALONG A PATH INCLINED TO THE BLADE INTO AND OUT OF CONTACT WITH A SURFACE OF THE BLADE AT THE CUTTING EDGE, AND A HAND GRASP ADJACENT TO THE END OF SAID MEMBER REMOTE FROM THE SHARPENING SURFACE FOR ENGAGEMENT BY AN OPERATOR TO RECIPROCATE SAID MEMBER. 